Modern vehicles typically have a multiplicity of embedded systems called Electronic Control Units (ECUs) configured to control one or more of their component electrical systems or sub-systems. For example, ECUs may be used to control a vehicle's engine, transmission, brakes, suspension, etc. A vehicle may therefore be typically configured with dozens of such ECUs to control its operation. ECUs may typically communicate between themselves using wired buses.
Most modern vehicles are also now equipped with a variety of wireless interfaces which increase their exposure/vulnerability to remote attacks by hackers and/or random interference from other wireless communications. Typically, an attack on an ECU may be achieved using any of its data connections (physical or wireless) and may consist of executing malicious code to gain control of the ECU. The compromised ECU may then be used as an entry point for the attack or further attacks such as, for example, sending malicious or illicit messages to other (sensitive) ECUs.